#define F_CPU 8000000

#include <avr/io.h>
#include <stdint.h>
#include <util/delay.h>
#include "pcf8591.h"

int ADCval;
uint8_t sine_wave[256] = {
	0x80, 0x83, 0x86, 0x89, 0x8C, 0x90, 0x93, 0x96,
	0x99, 0x9C, 0x9F, 0xA2, 0xA5, 0xA8, 0xAB, 0xAE,
	0xB1, 0xB3, 0xB6, 0xB9, 0xBC, 0xBF, 0xC1, 0xC4,
	0xC7, 0xC9, 0xCC, 0xCE, 0xD1, 0xD3, 0xD5, 0xD8,
	0xDA, 0xDC, 0xDE, 0xE0, 0xE2, 0xE4, 0xE6, 0xE8,
	0xEA, 0xEB, 0xED, 0xEF, 0xF0, 0xF1, 0xF3, 0xF4,
	0xF5, 0xF6, 0xF8, 0xF9, 0xFA, 0xFA, 0xFB, 0xFC,
	0xFD, 0xFD, 0xFE, 0xFE, 0xFE, 0xFF, 0xFF, 0xFF,
	0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFE, 0xFE, 0xFD,
	0xFD, 0xFC, 0xFB, 0xFA, 0xFA, 0xF9, 0xF8, 0xF6,
	0xF5, 0xF4, 0xF3, 0xF1, 0xF0, 0xEF, 0xED, 0xEB,
	0xEA, 0xE8, 0xE6, 0xE4, 0xE2, 0xE0, 0xDE, 0xDC,
	0xDA, 0xD8, 0xD5, 0xD3, 0xD1, 0xCE, 0xCC, 0xC9,
	0xC7, 0xC4, 0xC1, 0xBF, 0xBC, 0xB9, 0xB6, 0xB3,
	0xB1, 0xAE, 0xAB, 0xA8, 0xA5, 0xA2, 0x9F, 0x9C,
	0x99, 0x96, 0x93, 0x90, 0x8C, 0x89, 0x86, 0x83,
	0x80, 0x7D, 0x7A, 0x77, 0x74, 0x70, 0x6D, 0x6A,
	0x67, 0x64, 0x61, 0x5E, 0x5B, 0x58, 0x55, 0x52,
	0x4F, 0x4D, 0x4A, 0x47, 0x44, 0x41, 0x3F, 0x3C,
	0x39, 0x37, 0x34, 0x32, 0x2F, 0x2D, 0x2B, 0x28,
	0x26, 0x24, 0x22, 0x20, 0x1E, 0x1C, 0x1A, 0x18,
	0x16, 0x15, 0x13, 0x11, 0x10, 0x0F, 0x0D, 0x0C,
	0x0B, 0x0A, 0x08, 0x07, 0x06, 0x06, 0x05, 0x04,
	0x03, 0x03, 0x02, 0x02, 0x02, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x03,
	0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x0A,
	0x0B, 0x0C, 0x0D, 0x0F, 0x10, 0x11, 0x13, 0x15,
	0x16, 0x18, 0x1A, 0x1C, 0x1E, 0x20, 0x22, 0x24,
	0x26, 0x28, 0x2B, 0x2D, 0x2F, 0x32, 0x34, 0x37,
	0x39, 0x3C, 0x3F, 0x41, 0x44, 0x47, 0x4A, 0x4D,
	0x4F, 0x52, 0x55, 0x58, 0x5B, 0x5E, 0x61, 0x64,
	0x67, 0x6A, 0x6D, 0x70, 0x74, 0x77, 0x7A, 0x7D
};

void mcu_init (void);

long map(long x, long in_min, long in_max, long out_min, long out_max)
{
	return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}
int readADC(void){
	ADMUX = (ADMUX & 0xF0)|(0 & 0x0F);	//ADC0
	ADCSRA |= 1<<ADSC;					//Convert
	while(ADCSRA & (1<<ADSC));			//Wait until finished
	ADCval = (ADC>>6);					//Shift right 6 to use converted value
	ADCval = (int)map((long)ADCval, 0,1023,1,10);
	return ADCval;
}
/* Continuously reads analog value from channel 3 and then writes that analog value to the single DAC */
int main(void) {
	mcu_init();
	while(1){
		for(int value=0;value<256;value+=readADC()) {
			pcf8591_analog_write(sine_wave[value]);
			_delay_ms(1);
		}
	}
}
void mcu_init(void) {
	_delay_ms(10);
	pcf8591_init();
	
	//initialize ADC
	ADMUX = (1<<REFS0)|(1<<ADLAR);	//5V reference and left justified
	ADCSRA = (1<<ADEN);				//Enable ADC
	ADCSRB = 0x00;					//Free running mode
}